Leukemia Drug May Improve Stroke Treatment

June 23, 2008 -- A
leukemia drug may help make a clot-busting drug used to treat strokes more
effective and safer to use.

Blood clots in the brain cause about 80% of the 15 million strokes that
occur each year worldwide. Immediate treatment of these strokes is limited to
the use of tissue plasminogen activator (tPA), which works by dissolving
clots.

While tPa can reduce potential brain damage associated with
stroke, the downside is that it is only given within three hours of the
start of a stroke, and it carries the risk of dangerous bleeding in the
brain.

But a new study suggests giving the cancer drug Gleevec prior to tPA can
extend the time frame during which the clot-busting drugs are effective as
well as reduce the risk of bleeding in the brain. So far, the combination has
been studied only in mice, but researchers say the findings are promising.

"Our findings may have immediate clinical relevance, and could be
applied to find new treatments that will benefit stroke patients," says
researcher Daniel Lawrence, PhD, professor of cardiovascular medicine at the
University of Michigan Medical School, in a news release.

Cancer Drug for Stroke Treatment?

In the study, published in Nature Medicine, researchers examined the
effects of Gleevec on mice with induced strokes.

First, they induced strokes in two groups of mice and gave one group Gleevec
an hour after the stroke began.

The results showed mice that received Gleevec experienced less leakage in
the brain as a result of the stroke, and 72 hours later the Gleevec-treated
mice had 34% less brain damage than the others.

Then the researchers evaluated Gleevec as a pretreatment before clot-busting
tPA therapy. Mice were given Gleevec one hour after the stroke began and then a
dose of tPA five hours after the onset of the stroke.

Researchers assessed bleeding in the brain by measuring the amount of
hemoglobin in the stroke-affected side of the brain. Mice who received Gleevec
prior to tPA treatment had significantly less bleeding in the brain area than
those who didn't receive pretreatment.

Researchers say this last finding is especially encouraging because stroke
diagnosis often takes hours. If these findings are confirmed in humans,
Gleevec could be given immediately when a stroke is suspected to extend the
window in which tPA may be given.